The delivery of medicament through an animal's skin of an animal or of a person utilizing electrophoresis and/or electro-osmosis is one where the drug molecules in solution or suspension are made subject to an electric field, and in case of electrophoresis, if the electrode having the same charge as that of the ionic molecules is above the solution adjacent the skin which is the site of administration, the ions will be repelled and migrate through the skin into the blood stream; whereas in the case of electro-osmosis, a solution of water is attracted to the negative electrode, and thus any electric current flowing through a porous membrane causes a flow therethrough. Such electrochemical processes, although similar in end result do, however, function together, but separately or independently, in pumping and/or delivering a drug or other medication transdermally.
Transdermal drug applicators of the type being discussed herein are dependent upon application of electrical current to the electrical circuit including the drug reservoir(s) and the skin of the patient. Delivery of the drug to a patient, for example, is best accomplished at a steady state, at constant rate, often over a long period of time and/or on demand. Beneficial results of the drug transfer are lessened if the patient forgets at times to activate the drug delivery mechanism, so that delivery of the drug often takes place at the hospital. If the patient operates the delivery mechanism, delivery can be expected to be irregular.
It is therefor a principal object of this invention to provide a system that both mounts the drug applicator to the skin of a patient and that automatically times the activation and deactivation of an electrical power supply of the system to accomplish delivery and cessation of delivery of a drug by electrophoretic and/or electro-osmotic deposition at a variable controlled rate at preset or preprogrammed time intervals.
It is another object of this invention to provide a system that secures a drug reservoir or reservoirs to the skin of a patient and that includes a computer mechanism that can be programmed to signal the activation and deactivation of a power supply mounted in the system for delivery and cessation of delivery of a drug or drugs by electrophoretic and/or electro-osmotic deposition at a controlled rate at preset time intervals.
It is another object of the invention to provide a system which responds for controlling delivery of a drug to a patient that includes a response to physical and chemical changes experienced by the subject or patient, by providing a closed loop feedback system or in effect providing an on demand drug delivery system.
Other objects and advantages of this invention will hereafter become obvious from the following description of the preferred embodiments of this invention.
Reference to or disclosure of devices for transdermal delivery of drugs by application of electrical current through the skin of a person or animal are shown in the following U.S. Pat. Nos.:
______________________________________ 385,556 4,243,052 486,902 4,325,367 588,479 4,367,745 2,493,155 4,419,091 2,267,162 4,474,570 2,784,715 4,406,658 3,163,166 4,314,554 3,289,671 4,166,457 3,547,107 4,239,052 3,677,268 4,290,878 4,008,721 4,164,226 4,141,359 4,362,645 4,239,046 4,273,135 ______________________________________
The following foreign patents refer to or disclose transdermal delivery devices:
EPA 0060452 PA1 DE 290202183 PA1 DE 3225748 PA1 EPA 0058920 PA1 UK 2104388